Air blast circuit breakers



Jan. 8, 1963 R. SCHULZ 3,072,767

AIR BLAST CIRCUIT BREAKERS Filed Nov. 24, 1959 3 Sheets-Sheet 1 FIG. I

INVENTO'Q RAM/A MM k Mow M Jan. 8, 1963 Filed NOV. 24, 1959 R. SCHULZ AIR BLAST CIRCUIT BREAKERS 3 3 Sheets-Sheet 5 3M a, W W m.

United States Patent ,0 F

3,072,767 AIR BLAST CIRCUIT BREAKERS Richard Schulz, Friedberg, Hessen, Germany, assignor to Voigt & Haelfner A.G., Frankfurt am Main, Germany, a corporation of Germany Filed Nov. 24, 1959, Ser. No. 855,132 Claims priority, application Germany Dec. 3, 1958 Claims. (Cl. 200-148) This invention refers to gas blast circuit breakers, and more particularly to air blast circuit breakers, i.e. circuit breakers wherein the arcs drawn upon separation of pairs of cooperating contacts are subjected to, and extinguished by, the action of blasts of air.

This invention refers more particularly to air blast circuit breakers intended to be used in circuits whose operating voltage is high, say 220 kv., and wherein each pole unit is provided with a plurality of pairs of cooperating contacts which are serially related and form multibreaks upon separation thereof.

It is one object of this invention to improve the structures which are disclosed in my copending patent applications Ser. No. 610,868, filed September 19, 1956, for Fluid Pressure Operated Circuit Breaker Pole Units, now United States Patent 2,964,605 issued December 13, 1960; and Ser. No. 842,374, filed September 25, 1959, for Pneumatic Controls for High Voltage Air Blast Circuit Breakers. 7

Another object of this invention is to provide air blast circuit breakers comprising multiple storage means for air under pressure at ground potential and substantially ground level as well as at an elevated potential and at an elevated level immediately adjacent to the point, or points, where the circuit interrupting breaks are formed by parting of cooperating pairs of contacts, and of operatively relating these multiple storage means in such a way that the dangers resulting from faulty operation in case of a defect in some part of the pneumatic systern of the circuit breakers are minimized.

It is another object of the invention toprovide circuit breakers of the aforementioned character having multiple storage means for air under pressure which are oper-' atively related by check valves adapted to isolate a faulted part ofthe'pneurnatic system and allowing continued operation of the non-faulted part of the system with the fauted par-t cut-off or segregated therefrom. Other objects and advantages ofthe invention will become apparent as this specification proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the appended claims forming part of this specification.

For a better understanding of the invention reference may be had to the accompanying drawings in which:

FIG. 1 is a diagrammatic vertical section through a contactcarrying column of a pole unit of an air blast circuit breaker embodying the invention;

FIG. 2 is a diagrammatic section taken along 2-2 of FIG. 1 showing the constituent parts of the circuit breaker situated adjacent the top of the column in closed position;

. FIG. 3 is a section similar to that of FIG. 2 but showing the constituent parts of the circuit breaker in interrupting position, i.e. the position which causes formation ofan arc-quenching blast of air; and

T FIG. 4 is a section similar to that of FIGS. 2 and 3 showing the constituent parts of the circuit breaker in the oil-position, the position which they assume after cessation of the arc-quenching blast when the current carrying contacts remain separated.

Referringnow to the drawings, and more particularly tojFlG. 1 thereof, numeral 1 has been appliedto indi- 3,072,767 Patented Jan. 8, 1963 ice cate a tank or storage vessel for an pressure. Tank or vessel 1 is arranged at ground potential and close to ground level. Pipe line 2 is intended to supply tank or vessel 1 with air under pressure which may be derived from an air compressor (not shown). The vertical hollow insulating column 3 made of a suitable ceramic material is arranged above the tank or.vessel 1 and supported by it by the intermediary of a superstructure 1a. A condit 1b gives access to air under pressure contained in tank 1 to the interior of superstructure In from where it may freely flow into insulating column 3. Reference numerals 6 and 7 have been applied to indicate a pair of tanks or storage vessels for air under pressure which are arranged adjacent the upper end of insulating column 3, each to one side thereof. Each of the two tanks 6, 7 accommodates a pair of cooperating contacts and the cooperating contacts in both tanks 6, '7 are adapted to be serially connected into one phase of an electric circuit, as will be explained below more in detail in connection with FIG- 2. The housing 3a supported by the upper end of insulating column 3 is provided with a pair 7 of lateral air ducts 8, 9 for admitting air under pressure ton 4 slidably arranged in a cylinder 4a.

from column 3 to tanks 6 and 7. Housing 3a is subdivided by a partition 312 into a lower chamber and an upper chamber 10. The hollow insulating rod or pipe 20 projects transversely through partition 3b. Hollow rod or pipe 20 is movable in a direction longitudinally thereof and is guided by a gland 3c provided in partition 3b. It will be apparent from the foregoing that the air storage chamber 10 is arranged between the two air storage tanks 6 and '7. Air ducts 11, 12 make it possible to supply chamber 10 with air under pressure from either of thetwo tanks 6 and 7. Reference numerals 13, 14' have been applied to indicate a pair of check valves in ducts 1'1 and 12. Check valves 13, 1 4 are adapted to admit gas under pressure from tanks 6, 7 to storage chamber 10 and to preclude the back-flow of air from storage chamber 10 to tanks 6, 7. The flow of air under pressure from column 3 through the lower chamber formed by housing 3a into tanks 6, 7 is controlled by a pair of check valves 15, 16. This pair of check valves is adapted. to admit air under pressure from column 3 to tanks 6, and 7 but precludes any back-flow of air underpressure from tanks 6 and 7 to column 3. The lower end of hollow insulating rod 20 is connected to a hollow pis- Bell crank shaped operating lever 26 pivoted at 26a is-adapted to move piston 4 and hollow insulating rod 20 upwardly or downwardly, as desired. Rod 20 is a means for operating the control valve 21a which is arranged adjacent the top of column 3 and housing 3a at an elevated potential aboveground level. Hollow piston 4 receiving the lower end of hollow insulating rod 20 is at ground potential. Rod 20 is provided with an extension 20a slidably guided by a gland 3d in the top surface of housing 3a and directly connected to an operating arm of valve 21a. Coupling ZO'bconnects parts 20 and 20a and is adapted to admit air under pressure from chamber 10 into the hollow rod or tube 20. The lower end of'cylinder 4 is connected by pipe line or conduit 17 including check valve 21 to the dumping conduit 17 of tank '1. Dumping conduit 17 includes the, check valve 18, and ends in a dumping valve or dumping cock 19 which may be manually operable. In the'position shown in FIG. 1 dumping valve or cook 19 is closed. If rotated 90 degrees in clockwise direction (as seen in FIG. 1), dumping valve or cock'19 will open and dump air under pressure from tank 1 through check valve 18 and from tank or chamber 10 through hollow rod 20, hollow piston 4, cylinder 4a, conduit 17a andcheck valve 21. Inthe position of piston 4 and hollow rod 20 shown in FIG. 1 control valve 21a vents to atmosphere the two conduits 23, 24 which are connected to it. In the lower position of parts 4 and 20 control valve 21a connects the two conduits 23, 24 with conduit 22 which, in turn, is connected to chamber or air reservoir 10.

Air under pressure derived from tanks 6 and 7 is used for separation of the contacts of the circuit breaker and for establishing arc-extinguishing blasts through the gaps formed upon separation of the contacts. Air under pressure derived from reservoir 10 is used for what is generally referred to as the pneumatic control of the circuit breaker. This includes the pressure responsive means for initiating contact separation and the fluid motor means for causing opening of the blast valve. This will become more apparent from the ensuing description of FIGS. 2, 3 and 4.

Referring now to these figures, the two tanks 6, 7 and all the parts arranged therein are identical. Therefore only the contents of one of the tanks (tank 6) has been shown in section. Each tank 6, 7 is provided with a high voltage bushing 29'. The fixed plug type contact 27 is supported by the axially inner end of conductor stud 30 extending through bushing 29. Movable nozzle type contact 28 is adapted to cooperate with plug type contact 27. Nozzle type contact 28 is conductively connected to blast valve housing 31 of the left circuit breaker unit. The blast valve housing 31 of the left circuit breaker unit is, in turn, conductively connected to the blast valve housing 32 of the right circuit breaker unit. The nozzle type contact of the latter (not shown) is conductively connected to blast valve housing 32 and the plug type contact of the latter (not shown) is supported by the axially inner end of stud 33 extending through right hand bushing 29. The current path through the structure of FIG. 2 is thus as follows: stud 30, contact 27, contact 28, blast valve housing 31, blast valve housing 32, contacts (not shown) in tank 7 and stud 33.

The nozzle type contact 28 is supported by a piston 28a under the bias of a helical spring 34. Piston 28a supports by means of a spider 28b probe contact 35 and piston element 280. Piston element 280 is adapted to cooperate with the valve seat 37a arranged on the upper surface of blast valve body 37. Piston element 280 is arranged inside of cylinder 36 and slidably guided therein. Reference numeral 37b has been applied to indicate a fixed valve seat on blast valve housing 31 adapted to cooperate with the lower surface (as seen in FIGS. 2P4) of blast valve body 37. Blast valve body 37 is adapted to be operated by a fluid motor comprising piston 39. Piston 39 and blast valve body 37 are integrated by hollow piston rod 38 into a structural unit. Piston 39 is under the action of biasing spring 48 and is provided with a transverse hole 46 allowing to bleed air under pressure from one side of the piston to the other. Rod 42 arranged inside of hollow piston rod is provided with a valve element 42a on the side thereof remote from piston 39. Blast valve body 37 defines two ducts 45 and 47 both controlled by valve element 42a. In the position of valve element 42a shown in FIG. 2 duct 47 is open and duct 45 closed, whereas in the position of valve element 42 shown in FIGS. 3 and 4 duct 47 is closed and duct 45 open. Conduit 23 connects the chamber or reservoir 10 for air under pressure with the lower side of piston 39 (as seen in FIG. 2). In a similar fashion conduit 24 connects the chamber or reservoir 10 with one side of the blast-valve-operating piston for the right hand circuit breaker unit. Air under pressure is admitted to tanks '6 and 7 through pipes 8 and 9, as already mentioned in connection with FIG. 1. The check valves 15 and 16 for controlling the flow of air under pressure between column 3 and tanks 6, 7 have been omitted in FIG. 2. Air under pressure admitted to tanks space which is bounded radially outwardly by piston 28a and radially inwardly by probe electrode 35 is now vented through passage 5 to the outer atmosphere. Air under pressure in tank 6 moves piston 28a and contact 28 away from contact 27, causing separation of contacts 27 and 28 and drawing of an are between the separated contacts. The air blast sweeping through the gap formed between the separated contacts 27, 28 transfers one are terminal from contact 28 to probe electrode 35, thus causing the arc to be entirely enveloped by the blast of air and rapidly extinguished. The small opening 46 in piston 39 permits gradual equalization of the pressure to both sides of that piston. As a result, the force of spring 48 becomes preponderant and moves unit 39, 38, 37 to the initial position thereof. This results in re-closing of the blast gap formed between blast valve body 37 and fixed valve seat 37b and in re-loading of piston-biasing.- spring 34.

Upon admission of air under pressure to conduit 23 rod 42 and valve element 42a are moved in the direction of fixed contact 27. This causes venting of the space 44 bounded by piston element 280 and blast valve body 37 through duct 45. This allows piston element 28c and piston 28a to be moved by the pressure in tank 6 away from fixed contact 27, as has already been mentioned above. In the position shown in FIG. 3 the element 28c has moved as far as it can move away from fixed contact 27 while the arc-extinguishing blast is on, and valve body 37 has moved as far as it can move toward fixed contact 27, and parts 280 and 37 are in abutting relation. Numerals 40 and 41 have been applied to the juxtaposed surfaces of parts 280 and 37 bounding space 44. After parts 280 and 37 have assumed the position shown in FIG. 3 the pressure in tank 6 moves parts 28c and 37 jointly away from fixed contact 27 to the off position shown in FIG. 4 in which position the blast valve 37, 37a is re-closed. The space 44 bounded by surfaces 40 and 41 remains vented as long as the circuit breaker is in the open position thereof.

Reclosing of the circuit breaker is effected by turning bellcrank-shaped lever 26 in clockwise direction to cause parts 4, 20, 20a and 21a to assume the position shown in FIG. 1 wherein control valve 21a vents the two pipe lines or conduits 23, 24 to atmosphere. As a result, the pressure maintaining parts 42 and 42a in the position shown in FIGS. 3 .and 4 subsides, and these parts now are moved by air under pressure inside of tank 6 entering into duct 47 in a direction away from fixed contact 27. Moving of valve element 42a from its valve seat situated on the side of contact 27 to its valve seat situated on the side opposite of contact 27 causes closing of venting duct 45 and opening of duct 47. The space 44 bounded by surfaces 40 and 41 will now be filled with air under pressure entering into it through duct 47. When the space 44 bounded by surfaces 40 and 41 is filled with air under pressure the thrust of spring on parts 28a, 35, 28b, and 28c predominates and causes movement of these parts toward fixed contact 27 and re-engagement of fixed contact 27 by movable contact 28. Thus the constituent parts of the circuit breaker assume again the position shown in FIG. 2.

If the pressure in tank 1 or column 3 drops below a predetermined value check valves 15 and 16 close and thus maintain the required operating pressure in tanks 6 and 7. Hence the circuit breaker remains operative in spite of a leakage or other damage causing a reduction of the pressure inside of tank 1 and column 3.

Assuming tank 6develops a leakage, this results in closing of check valves 13 and 15. Hence pressure will be fully maintained in tanks 7 and 10. This allows to open and to close the pair of cooperating contacts which are arranged inside of tank 7 (corresponding to contacts 27, 28 in tank .6).

Assuming'that there is some reduction of pressure inside of tanks 6 and 7, it will be apparent that check valves '13 and 14 preclude a similar or concomitant reduction of pressure from taking place inside of chamber or reservoir 10 for air under pressure. This is a highly desirable feature because it assures positive operation of the circuit breaker at all times.

It will be apparent that conduits 11 and 12 between 'tanks 6 and 7 and chamber 10 might include pressure reduction means for establishing a lower pressure level in tank 10 than that prevailing in tanks 6 and 7. It is often desirable to operate the controls of an air blast circuit breaker at a lower pressure level than that required for establishing the arc-extinguishing blast since a relatively lower pressure level inside the control system allows to achieve substantial economies in laying out the latter.

Repairs or maintenance operations may make it necessary to empty all storage means for compressed air, i.e. tanks 1, 6, 7 and 10. To this end dumping valve or cock 19 is opened. This allows air under pressure inside of tank 1 to escape through pipe 17 and check valve 18. Air under pressure in tank 10 can escape through hollow rod 20, hollow piston 4, pipe 17a and check valve 21. Air under pressure inside tanks 6 and 7 can escape through check valves 13 and 14 into tank 10, .and from there through parts 20, 4, 17a and 21 to dumping valve 19.

It will be understood that although but one embodiment of the invention has been illustrated and described in detail, the invention is not limited thereto. It will be further understood that the structure illustrated may be modified without departing from the spirit and scope of the invention as set forth in the accompanying claims.

I claim as my invention.

1. A gas blast circuit breaker comprising a vertical insulating column, a pair of cooperating separable contacts arranged adjacent the upper end of said column, a fluid motor for causing separation of said pair of contacts including means responsive to gas under pressure for initiating operation of said fluid motor, a blast valve for causing an arc-extinguishing blast of gas to flow through the gap formed between said pair of contacts upon separation thereof by said fluid motor, said blast valve including means responsive to gas under pressure for causing opening of said blast valve, means arranged adjacent said upper end of said column defining a first chamber supplied with gas under pressure through said column and supplying gas under pressure for causing said arc-extinguishing blast of gas, means defining a second storage chamber for gas under pressure arranged adjacent the upper end of said column separate from said first chamber, said'means defining said second chamber including fixed partition means precluding said second chamber from being supplied with gas under pressure directly from said upper end of said column, a check valve adapted to admit gas under pressure from said first chamber to said second chamber and to preclude the admission of gas under pressure from said second chamber to said first chamber, and control valve means for admitting gas under pressure from said second chamber to said means for initiating operation of said fluid motor and to said means for causing opening of said blast valve.

i2- A gas blast circuit breaker comprising a vertical insulating column, a first tank for gas under pressure arranged at the lower end of and supporting said column,

a pair of tanks arranged adjacent the upper end of said column and adapted to be supplied through said column with gas under pressure derived from said first tank, a second tank arranged adjacent the'upper end of said column between said pair of tanks, fixed partition means precluding said second tank from being supplied with gas under pressure directly from said column, check valve means adapted to admit gas under pressure from said pair of tanks to said second tank, two pairs of separable contacts each inside of one of said pair of tanks, a pair of fluid motors each for causing separation of one of said pairs of contacts and each of said pair of fluid motors including means responsive to gas under pressure for initiating operation thereof, a pair of blast valves for causing blasts of gas under pressure derived from said pair of tanks to flow through the gaps formed between said two pairs of contacts upon separation thereof by said pair of fluid motors, said pair of blast valves including means responsive to gas under pressure for causing opening of said pair of blast valves, and control valve means for admitting gas under pressure from said second tank to said means for initiating operation of said pair of fluid motors and to said means for causing opening of said pair of blast valves.

3. A gas blast circuit breaker comprising a vertical insulating column, a first tank for gas under pressure arranged at the lower end of said column, a second tank arranged adjacent the upper end of said column, a third tank arranged adjacent the upper end of said column and adapted to be supplied through said column with gas under pressure derived from said first tank, a first check valve adapted to admit gas under pressure from said column to said third tank and to preclude back-flow of gas under pressure from said third tank into said column, a second check valve adapted to .admitgas under pressure from said third tank to said second tank and to preclude back-flow of gas under pressure from said second tank to said third tank, fixed partition means precluding said second tank from being supplied with gas under pressure directly from said column, a pair of separable contacts arranged inside said third tank and spring-biased to the closed position thereof, a first fluid motor for causing separation of said pair of contacts against spring bias, a venting valve for initiating operation of said first fluid motor, a blast valve for causing a blast of gas under pressure to flow through the gap formed between said pair of contacts upon separation thereof by said first fluid motor, said blast valve including a second fluid motor for causing opening thereof, and control valve means for admitting gas under pressure from said second tank to said venting valve and to said second fluid motor.

4. A gas blast circuit breaker comprising a vertical insulating column, a first tank for gas under pressure arranged adjacent the lower end of said column, a second tank for gas under pressure arranged adjacent the upper end of said column, fixed partition means precluding said second'tank from being supplied with gas under pressure directly from said column, a third tank for gas under pressure arranged adjacent the upper end of said column and adapted to be supplied through said column with gas under pressure derived from said first tank, a check valve adapted to admit gas under pressure from said third tank to said second tank and to preclude back-flow of gas under pressure from said second tank to said third tank, a pair of cooperating separable contacts arranged adjacent the upper end of said column, a first fluid motor for causing separation of said pair of contacts, said first fluid motor including means responsive to gas under pressure for initiating operation thereof, a blast valve for causing a blast of gas under pressure derived from said third tank to flow through the gap formed between said pair of contacts upon separation thereof by said first fluid motor, a second fluid motor for causing opening of said blast valve, a joint control valve means for admitting gas under pressure from said second tank to said means 7 for initiating operation of said first fluid motor and to said second fluid motor, a dumping valve for said first tank, and pipe means for connecting said second tank to said dumping valve to permit simultaneous dumping of gas under pressure from said first tank, said third tank and said second tank.

5. A gas blast circuit breaker comprising a vertical insulating column, a first tank for gas under pressure arranged adjacent the lower end of said column, a second tank for gas under pressure arranged adjacent the upper end of said column, fixed partition means precluding said second tank from being supplied with gas under pressure directly from said column, a third tank for gas under pressure arranged adjacent the upper end of said column and adapted to be supplied through said column with gas under pressure derived from said first tank, a check valve adapted to admit gas under pressure from said third tank to said second tank and to preclude back-flow of gas under pressure from said second tank to said third tank,

a pair of cooperating separable contacts arranged inside 20 said third tank, a first fluid motor for causing separation of said pair of contacts, said first fluid motor including means responsive to gas under pressure for initiating operation thereof, a blast valve for causing a blast of 8 gasunder pressure derived from said third tank to flow through the gap formed between said pair of contacts upon separation thereof by said first fluid motor, a second fluid motor for causing opening of said blast valve, a control valve means arranged adjacent the upper end of said column for admitting gas under pressure from said second tank to said means for initiating operation of said first fluid motor and to said second fluid motor, a tubular insulating rod arranged inside of said column and adapted to operate said control valve means from the bottom region of said column, a manually operable dumping valve for said first tank, pipe means for connect-' ing said second tank to said dumping valve to permit simultaneous dumping of gas under pressure from said first tank, said thirdtank and said second tank, and said pipe means including said tubular insulating rod.

References Cited in the file of this patent UNITED STATES PATENTS 2,803,724 Forwald Aug. 20, 1957 FOREIGN PATENTS 1,013,347 Germany Aug. 8, 1957 

1. A GAS BLAST CIRCUIT BREAKER COMPRISING A VERTICAL INSULATING COLUMN, A PAIR OF COOPERATING SEPARABLE CONTACTS ARRANGED ADJACENT THE UPPER END OF SAID COLUMN, A FLUID MOTOR FOR CAUSING SEPARATION OF SAID PAIR OF CONTACTS INCLUDING MEANS RESPONSIVE TO GAS UNDER PRESSURE FOR INITIATING OPERATION OF SAID FLUID MOTOR, A BLAST VALVE FOR CAUSING AN ARC-EXTINGUISHING BLAST OF GAS TO FLOW THROUGH THE GAP FORMED BETWEEN SAID PAIR OF CONTACTS UPON SEPARATION THEREOF BY SAID FLUID MOTOR, SAID BLAST VALVE INCLUDING MEANS RESPONSIVE TO GAS UNDER PRESSURE FOR CAUSING OPENING OF SAID BLAST VALVE, MEANS ARRANGED ADJACENT SAID UPPER END OF SAID COLUMN DEFINING A FIRST CHAMBER SUPPLIED WITH GAS UNDER PRESSURE THROUGH SAID COLUMN AND SUPPLYING GAS UNDER PRESSURE FOR CAUSING SAID ARC-EXTINGUISHING BLAST OF GAS, MEANS DEFINING A SECOND STORAGE CHAMBER FOR GAS UNDER PRESSURE ARRANGED ADJACENT THE UPPER END OF SAID COLUMN SEPARATE FROM SAID FIRST CHAMBER, SAID MEANS DEFINING SAID SECOND CHAMBER INCLUDING FIXED PARTITION MEANS PRECLUDING SAID SECOND CHAMBER FROM BEING SUPPLIED WITH GAS UNDER PRESSURE DIRECTLY FROM SAID UPPER END OF SAID COLUMN, A CHECK VALVE ADAPTED TO ADMIT GAS UNDER PRESSURE FROM SAID FIRST CHAMBER TO SAID SECOND CHAMBER AND TO PRECLUDE THE ADMISSION OF GAS UNDER PRESSURE FROM SAID SECOND CHAMBER TO SAID FIRST CHAMBER, AND CONTROL VALVE MEANS FOR ADMITTING GAS UNDER PRESSURE FROM SAID SECOND CHAMBER TO SAID MEANS FOR INITIATING OPERATION OF SAID FLUID MOTOR AND TO SAID MEANS FOR CAUSING OPENING OF SAID BLAST VALVE. 